Photoexcitation Altered Reaction Pathway Greatly Facilitate Ammonia Synthesis Over Isolated Ru Sites

Ammonia, poised as a carbon-neutral energy carrier, holds immense promise in reshaping the future energy landscape. Despite the enduring importance of the Haber-Bosch process in ammonia production, its substantial carbon emissions and energy demands necessitate more sustainable pathways. Here, an advanced ammonia synthesis route, enhanced by photoexcitation is demonstrated, which fundamentally modifies the activation pathways of N2 molecules. This alteration significantly lowers the reaction activation energy, resulting in remarkably improved reaction efficiency. The impact of light excitation culminates in an unprecedented ammonia synthesis rate of 18 mmol g-1 h-1, surpassing the traditional thermal catalytic process by 2.57-fold. More importantly, light assistance reduces the thermal energy input by approximate to 16%, making it comparable to thermal catalysis while substantially improving energy utilization. This work introduces a greener strategy for ammonia synthesis, pushing the century-old fossil-fueled Haber-Bosch process to a new frontier. The photoexcitation compensates for the insufficient catalyst charge density in thermalcatalytic ammonia synthesis. Ru-decorated-CeO2 demonstrates the advantage of local charge compensation under irradiation, fostering the gathering of photogenerated electrons toward Ru sites. The electron-rich Ru sites facilitate the distal pathways, leading to a substantial enhancement in thermocatalytic ammonia synthesis and a reduction in thermal energy input. image